• Bulletin of the Korean Chemical Society
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• 제33권10호
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• pp.3497-3500
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• 2012

• Bulletin of the Korean Chemical Society
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• 제17권12호
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• pp.1178-1181
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• 1996

• Bulletin of the Korean Chemical Society
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• 제32권spc8호
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• pp.3017-3021
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• 2011

Two chiral stationary phases (CSPs) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 bonded covalently to silica gel were applied for the first time to the resolution of racemic vigabatrin and its analogue ${\gamma}$-amino acids and the resolution results were compared to those on the commercially available Crownpak CR(+) based on (3,3'-diphenyl-1,1'-binaphthyl)-20-crown-6 coated dynamically onto octadecylsilica gel. While vigabatrin was not resolved at all on Crownpak CR(+), it was resolved quite well on the two CSPs. Among four vigabatrin analogue ${\gamma}$-amino acids, only two were resolved on Crownpak CR(+), but three were resolved on the CSP (CSP 1) containing residual silanol groups and all of four were resolved on the CSP (CSP 2) containing residual silanol group-protecting n-octyl groups. The improved lipophilicity in CSP 2 was proposed to be responsible for its superiority to CSP 1 for the resolution of vigabatrin and analogue ${\gamma}$-amino acids. In addition, the composition of aqueous mobile phase was found to affect the chiral recognition behaviors for the resolution of vigabatrin and analogue ${\gamma}$-amino acids on CSP 2.

• KSBB Journal
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• 제25권5호
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• pp.449-452
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• 2010

크라운 에테르로부터 유도된 키랄고정상에서 역상용매를 이동상으로 사용하여 국내외에서 시판되고 있는 광학이성질체 의약품인 레보티록신 나트륨의 광학순도 측정을 위한 새로운 직접적인 광학분리 분석법을 개발하여 매우 좋은 결과를 얻었다 ($\alpha$ = 2.15, Rs = 4.05). 시판하고 있는 레보티록신 나트륨의 광학순도를 키랄고정상을 이용하여 직접적인 광학분리방법으로 측정하는 실험은 현재까지 한 편의 연구결과 외에는 보고되어 있지 않는데 [4] 본 연구에서 새롭게 개발한 전처리과정과 HPLC 분석조건을 이용하여 현재 국내외에서 판매되고 있는 레보티록신 나트륨 주성분의 의약품 정제의 광학순도를 측정하였다. 레보티록신 나트륨의 광학순도를 측정한 광학분리 실험결과에서 하나의 제품을 제외하고는 99% 이상의 높은 광학순도를 보여주고 있음을 확인할 수 있었다. 본 연구의 편리하고 용이한 신규 광학분리 분석법이 국내외에서 상용되는 레보티록신 나트륨 제품의 품질 확인과 양질의 키랄의약품을 개발하고 제품을 관리하는데 매우 도움이 되리라 기대한다.

• Bulletin of the Korean Chemical Society
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• 제22권9호
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• pp.958-962
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• 2001

The chiral amine auxiliary mediated stereoselective alkylation reactions of glycinamides 1-6 and 15-17 using phase transfer catalyst (PTC) for liquid-solid extraction are described. The secondary N-(diphenylmethylene) glycinamides 1, 2 and 3 give better selectivities and yields than tertiary N-(diphenylmethylene) glycinamides 4, 5 and 6. Alkylation of the glycinamide 1 and 2 using 18-Crown-6 as a PTC in toluene at $-40^{\circ}C$ gives best selectivities and yields. Alkylations of N-(4-chlorophenylmethylene)glycinamides 15, 16 and 17 under same PTC conditions give $\alpha$, $\alpha-disubstituted$ amino acid derivatives 18, 19 and 20 with low diastereoselectivities.

• Bulletin of the Korean Chemical Society
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• 제33권12호
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• pp.4141-4144
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• 2012

This paper introduces a technique for resolving amino acids that combines the advantages of the conventional CSP (chiral stationary phase) method with the CMPA (chiral mobile phase additive) method. A commercially available chiral crown ether column, CROWNPAK CR(+), was used as the CSP and three cyclodextrins (${\beta}$-CD, ${\gamma}$-CD, HP-${\beta}$-CD) were used as the mobile phase additives. Chromatographic resolution was performed at $25^{\circ}C$ and $50^{\circ}C$ with or without sonication. A comparison of the chromatographic results under ultrasonic conditions with those under non-ultrasonic conditions showed that ultrasound decreased the elution time and enantioselectivity at all temperatures. In the case of the ${\beta}$-CD mobile phase additive, the elution time and enantioselectivity under ultrasonic condition were significantly higher than under non-sonic condition at all temperatures. Commercially available Chiralpak AD, Whelk-O2 and Pirkle 1-J columns were used as CSPs to examine more meticulously the effects of ultrasonication and temperature on the optical resolution. The optical resolution of some chiral samples analyzed at $25^{\circ}C$ and $50^{\circ}C$ with or without sonication was compared. As in the previous case, the enantioselectivity was lower at $25^{\circ}C$ but similar enantioselectivity was observed at $50^{\circ}C$.

• 분석과학
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• 제9권1호
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• pp.52-61
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• 1996

식품 중의 몇몇 유리 D-아미노산이 column switching method에 의해 검출되었다. D-아미노산과 L-아미노산의 총량의 정량은 $C_{18}$ 컬럼을 사용한 비키랄 분리에 근거한다. L-아미노산에 대한 D-아미노산의 수준은 o-phthalaldehyde로 유도체화된 아미노산의 postcolumn reaction detection을 포함하는 column switching system에 의해 정량되었다. Postcolumn detection system의 키랄 분리는 chiral crown ether 컬럼에 의해 실행되었다. 이 system은 간장과 발효된 콩, 그리고 콩 같은 식품 중에 있는 D-아미노산의 정량에 적용된다. 이 achiral/chiral coupled-column system하에서는 시료 전처리과정이 중요함을 알게 되었다. Phenylalanine은 시판용 간장 속에 242ppm, 재래식 간장 속에는 102ppm, 발효된 콩에는 1g당 8.34mg, 콩에는 1g당 2.87mg이 함유된 것으로 밝혀졌다. D-phenylalanine은 시판용 간장 속에는 0.67%, 재래식 간장에는 0.34%, 발효된 콩에는 1.81% 미만, 콩에는 2.82% 미만이 검출되었다.

• Bulletin of the Korean Chemical Society
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• 제32권2호
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• pp.503-509
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• 2011

New types of lariat type crown ethers containing peptide sidearms were prepared by using a novel strategy employing single electron transfer (SET)-induced photocyclization reactions of $\alpha$-silylether terminated phthalimides. Reactions of chiral substrates in this series produced diastereomeric mixtures of crown ether products as a result of the formation of new stereogenic center generation in the photocyclization process.

• Bulletin of the Korean Chemical Society
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• 제29권5호
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• pp.1069-1072
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• 2008

• Bulletin of the Korean Chemical Society
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• 제28권11호
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• pp.2020-2024
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• 2007

The article reports the synthesis of a novel bispyridino-18-crown-6 ether, 7-{[(5S,15S)-5,15-diphenyl- 3,6,14,17-tetraoxa-23,24-diazatricyclo[17.3.1.18,12]tetracosa-1(23),8(24),9,11,19,21-hexaen-10-yl]oxy}heptylferrocenamide 6, bearing the C2-symmetric diphenyl substituents as chiral barriers and the ferrocenyl groups serving as an electrochemical sensor, and its electrochemical study with D- and L-AlaOMe·HCl as the guest by cyclovoltametry.